Phonograph



Oct. 20l 1925. 1,558,048

' H. ROTH KIRCH PHONOGRAPH Filed Nov. 8, 1921 2 Sheets-Sheet l @Umluft/IH WIM/ESS ff/WWW A TTURNEYS Oct. 20,1925.

H. ROTHKIRCH PHONOGRAPH Filed Nov'. e, 1921 2 Sheetsfsheet 2 A TTORNEYS Patented Oct. 20, 1925.

UNITED STATESA HERMAN ROTHKIRCH, OF NEW YORK, N. Y.

IPHONOGRAPH.

Application filed November 8, 1921. rSerial No. 513,747.

To all 'whom t may concern:

Be it known that I, HERMAN ROTHKIRGH, a citizen of the United States, and resident of the borough and county of Queens, city and State of New York, have invented certain new and useful Improvementsin Phonographs, of which the following is a specilication.

My invention relates to phonographs and has for its object to provide such instruments with a tone arm constructed entirely of wood in a novel manner and whereby all objectionable and foreign noises are elimiw hated from the reproduction of the record. A further object of the invention is to .pro

vide such a tone arm with a reproducer constructed as an integral part thereof and consisting, excepting as to the diaphragm and needle arm, also entirely of wood. Other more specific objects of my invention will appear from the description hereinafter and vthe features of novelty will be pointed out in the appended claim. v n,

r The present application is, in part, a continuation of another application filed by me in the United States Patent Oliice on or about April 7, 1921, Serial No. 459,300.

`In the accompanying` drawings, which illustrate examples of my invention without defining its limits, Figure 1 is a perspective view of my improved tone arm-and so much of a phonograph as is necessary to illustrate the invention; Fig. 2 is an end elevation of the tonearm; Fig. 3 is a fragmentary, inverted plan view thereof; Fig. 4 is an elevation of the combined tone arm and reproducer, with parts in section; Fig. 5 is a longitudinal section thereof; Fig. 6 is a 'section on the line 6-6 of Fig. 4; Fig. 7 is a section on. the line 7-7 of Fig. 4; Fg'- 3 is a similar View on the line 8-8 of Fig. '4; Fig. 9 is a detail section onthe line 9 9 of Fig. 8, and Fig. 10 is a detail section illustrating a sound controlling device which may form a part of the construction. *n

In the drawings, 10 indicates the rotating table ,of a phonograph mounted in the customary manner upon an arbor 11 which, as usual, comprises a part of and is operated by a spring'motor in the well known way. 12 represents the casing of a phonograph which may be constructed in ,any conven tional manner to include a sound conduit 13 and such other features usually are found in instruments of the character referred to. Inl the form shown in Figs. 1, 2 and 3 the tone arm 14 is of rectangular cross-section and is constructed entirely of wood in a curved form, as shown in Fig. 1, and at its forward end communicates with and carries the reproducer 15 which, in this form, may be of kany existing type or constructed in any special manner for special cofoperation with thetone arm in question..y Vhen constructed as a separate unit in the customary way, the reproducer 15 may be detachably secured to the tone arm in `any conventional manner. The upper and lower walls tand b, respectively, of the tone arm 14 are bent into curved form in the direction of their length whereby at least some of thefibres of the wood are placed `under tension and the frequency of vibration of the tone arm is altered to improve its qualities as a sound conduit. The side walls c of the' tone arm are curved to properly tit the upper and lower walls a and b thereof, as shown in Fig. 1, and may be connected therewith by gluing or in any other suitable manner. The ytone arm 14, in the illustrated example shown in Figs. 1, 2 and 3, extends through a suitable opening 16 in the top of the casing 12, so that its inner end communicates with the sound conduit 13. The tone arm may be mounted forsupport in a horizontal plane in any convenient vway and may, for

instance, be provided with a pivot member 17 of wood which is seated in a socket 18 formed in a coupling head 19 suitably mounted wit-hin the casing 12. In order to secure the tone arm 14 against` unintentional removal without interfering with its pivotal movements, the pivot 17y may be provided with a lug 2O adapted to project beneath a `flange 21 of the coupling head 19. The flange 21 extends only partly about the coupling head 19 and forms an opening 22 "through whichA the lug 20 may be passed in one position to disconnect the tone arm 14 from the coupling head. vThe opening 22 1s vso located that it is necessary, in order i'o permit disconnection of said tone arm from v,the coupling head, to bring` the tone arm to a position other than the positionassumed by it in the operation ofthe instrument. Whileitis thus possible, wit-h this arrangement. to readily disconnect the tone arm when this is desired for any reason, said,

tone arm is efliciently protected against uuintentional or accidental disengagement from the coupling head 19.

In the form shown in Figs. l to S inclusive, the tone arm includes, as an integral part, the reproducer which is constructed of wood and consists ot a casing 23 formed with an interior spiral passage 24 constituting a continuation of the tone arm passage and terminating in an open-ing 25 in the front face of the casing 23. The passage tapers gradually in direction toward the opening 25, as shown in Fig. 5, and also becomes gradually smaller in va transverse direction vas it `approaches ,said opening, as illustrated in Fig. 6. The combined reproducer and tone :arm may be said to comprise a sound `conduit Vof which the casing 23 is the head yand the tone yarm l the body. An annular ,flange 26 ,is located upon .the `rfront face of .the `casing 23 -in .concentric relation to .the opening 25, .which it encircles, and forms a support for the customary diapln'agm 27 which is fastened in place by means .of a ring 28 of Wood and sscrews 29, as Vshown in Fig. 4. The ring 28 serves as a'support for bearing members 30, which are also of wood, and between which the .stylus arm 31 is pivotally mounted by means .of .pivot screws .32 lin the well known manner; at .one end, said arm 31 is connected with the diaphragm 27, .as usual, while a-t its rtree .end said arm is provided with the customary ,socket 3,3 in which the needle is removably secured by means of .the conventional set Ascrew 34.

In the form .of tone yarm being described the walls a, 'b and o are preferably bowed to a .slight extent, as shown in Fig. 7, whereby the .fibres of the wood at the indicated points of these walls .are placed under tension -to still further increase the resonance of the tone arm; in the preferred form, the outward bowing of said ,walls is confined to the vicinity of the exit :end of the tone arm, said walls being gradually flattened ou-t as thc free .end of .the ,tone arm is approached.

The tone arin under Idisaission may, .as shown7 also .be provided with members 35 which project .outwardly from the walls a, b a and together constitute ,a circula-r flange vor disk whereby the @Plllg A16 of .the .casing 12 is covered, as indicated in 5; the members 3,5 4are shaped `so as not to interfere with lthe rocking movements of the tone arm. In .the preferned form the inembers 35 .engage the walls a, Z) `and Yc only at spaced .points and are free therefrom between. such points, as shown in Fig. 7 ywith this arrangement. oppositionto the vibratio-n .ofsaid walls by' the ,action ofthe sound iva-.ves V.is .reduced to ya minimum Vand the resonance ,of .the tone is not interfered with to any appreciable extent.

In the form of construction illustrated in Figs. 41 to 8 inclusive, the coupling head 19 is pivotally mounted at 19h to swing about a horizontal axis instead of being lixed as in Fig. 1. Similarly the pivot 17 is provided with a pin 20 which corresponds to the lug 2O and which is arranged to extend and move beneath a flange 21 corresponding to the fiange 21 of Fig. 1. By bringing the tone arm to a position other than any position assumed by it in the operation of the instrument, said pin 20 is moved from beneath the flange 21n and thus permits the tone arm to be disconnected from the coupling head 19a. By pivotally mounting the latter, as illustrated, the automatic adjustability of the tone arm to any vibrating or undulating movements of the record or table 1() is facilitated.

It will 'be understood that any .of the features specifically set forth with respect to the form shown in Figs. 4 .to 8 inclusive may be included in the form shown in Figs. 1 to 3 inclusive and vice versa.

By constructing the tone arm, inthe manner described,entirely of `wood in which at least Asome of the fibres areA placed under tension -the resonance of said tone arm is materially increased and the reproductive or tonal quality of the instrument is greatly improved. The absence of any metal in said tone arm also avoids the production of any metallic sounds when the record is being reproduced. The quality of the tone arm in particular and the instrument in general, from vthe standpoint of reproduction or tone, is still further increased by constructing the tone arm and reprodueer as a unit, as` shown in Figs. 4 vto 8 inclusive. lVith this arrangement all metallic sounds are eliminated and the sound waves, free from any objectionable and disturbing sounds, are conducted by the passage 2-1 to the interior of the tone arm tand permitted to gradually expand without losing any of their original qualities and .to finally issue forth from the exit end of .the sound couduit 13 in a maximum .of volume and tonal purity. The tone arm, in is simple in .construction and may be produced in manner adapting it for co-.operation with existing types of phonographs.

As shown in Fig. 10, a member 36 may be all of its forms, .f

pivotally-mounted upon the reproducer in such a manner .that its one end is movable across the passage 241, preferablyl near its inlet end whereby the open area of said passage may be adjusted .at this point to regulate the volume of sound escaping from the instrument. The member 86 extends beyond the casing I23 in the form of a readily accessible y.handle 37 whereby said member Uniayfbe manipulated without effort to Aprovide the desired regu-lation and also to produce predetermined effects, such as a grad ual increase or decrease or both in the volume of sound.

Various modications in the specific form "5 shown and described may be made Within the scope of the claim Without departing from the spirit of my invention.

I claim: In a phonograph, a tone arm of unbroken 1U curved continuity constructed of Wood,

said tone arm being of polygonal crossseetion and having its Walls curved in lengthwise directions and also bowed out- Wardly at predetermined points in transverse directions to place the Wood fibres under tension.

In testimony whereof I have hereunto set my hand.

HERMAN ROTHKIRCI-I. 

